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Old 07-08-2017, 09:38 AM   #1
momaka
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Default XFX GeForce 8600 GT [PV-T84J-UDD3 V6.5] GPU recap

Another one of these XFX GeForce 8600 GT video cards saved from the electronics scrap yard!
This one is a version 6.5. Technically, it is the same exact thing as version 5.0 from the other thread I created a while back. But I decided to make a new thread for this, as the other one got a bit off-topic with me erroneously concluding that the card was failed. So here goes another one.

As usual, I got this 8600 GT from eBay too. But unlike the previous one, look at what we have here:
http://www.badcaps.net/forum/attachm...1&d=1499527964
http://www.badcaps.net/forum/attachm...1&d=1499527964

This 8600 GT came with pretty much all of the original box contents (including the game, “Company of Heroes”). I am the type of person that likes to keep original boxes, cables, and CDs with my hardware, so I find this awesome!

Now let’s see the card from up close:


Uh-oh - busted Sacon FZ all over again. Let’s have a closer look, shall we?


Ugh! It's like a dejavu of the other 8600 GT. The RAM has both of its caps busted. That’s always risky, as I have two EVGA GeForce 7600 GT video cards that smoked their RAM due to this. But again, the seller of this auction reassured me that the card was working when it was taken out of service. So I took his word and began my recap.

Step 1: Give the video card a Sacon-be-Gone treatment. My spray can of that stuff ran out, so I had to do it manually with a soldering iron

- Ah! Much better!

Step 2: Solder replacement caps.

I probably went a bit more minimalist here than I normally do, as I did nothing to replace the bulged FZ caps on the 12V rail (only left the blue Chemicon PSA polymers). But this was just for testing, after all. I also used more Chemicon PSA caps as the replacement for some of the FZ, just for the sake of consistency and color-matching .

By the way, note the corrosion on the SMD cap pads – not sure why, but it was pretty terrible on this video card. I cleaned them all before soldering my “new” caps.

Step 3: test.

Well, it works alright. But for how long? –Probably not much if under load / gaming. Look at these core temperatures:


At a 21C / 70F room temperature and open PC case, the GPU core temperature easily reached 62C (and still rising) after about 20-30 seconds under medium-high load. Clearly, the heatsink is not adequate here, just like on the previous 8600 GT. It will surely need a modded heatsink of some sort.

So now that the card was working, I made a cap diagram for it, so you can see which caps are connected to which rail. Technically, I didn’t really need to make one, as this video card has the same exact layout and design as the v5.0 8600 GT – so if you’ve read through that thread, you may find the information here a bit redundant. On the other hand, the cap diagram in this thread may be easier to follow than the text description in my other thread.

Cap diagram:

If I remember correctly, these were the voltages for the rails above:
GPU V_core: 1.4 Volts
RAM Vdda/Vddq: 1.8 to 2 Volts, depending on RAM type (Infineon typically takes 2V)
GPU Vtt: 1.25 Volts

And finally, I save the best for last. The icing of the cake, as they say.
Let’s see how bad those Sacon FZ caps are once they poped. Ladies and gentlemen, I present you Sacon FZ at their finest:



Lol, look at these c[r]aps! They are a hair away from open-circuit. . Not even two (2) nanoFarads of capacitance in any of them! I think it is an absolute miracle this video card worked at all!

Now that the video card is recapped, the only thing that can kill it is heat. So for this, we need us a modified heatsink that will keep the core lower than 60C. But that would be material for another post. I am already experimenting with my first 8600 GT. Once I come up with a good heatsink mod that is both quiet and cool, I will then make the same one for this video card.

Last edited by momaka; 07-08-2017 at 09:48 AM..
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Old 07-08-2017, 10:02 AM   #2
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Default Re: XFX GeForce 8600 GT [PV-T84J-UDD3 V6.5] GPU recap

Thanks momaka, an interesting read as always.
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Old 07-08-2017, 02:26 PM   #3
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Default Re: XFX GeForce 8600 GT [PV-T84J-UDD3 V6.5] heatsink comparison

You are welcome, diff.

Also, just to show that there is a small difference between the v5.0 and v6.5 8600 GT, let's have a look at their heatsinks.

Here are the two heatsinks side-by-side (or one above other, I should say). On the top is the v6.5 heatsink, and on the bottom v5.0.
http://www.badcaps.net/forum/attachm...1&d=1499545505

Version 6.5 uses a squirrel cage fan, so the heatsink has holes underneath the fan area to allow the fan to intake air. The fins on the heatsink are straight and air is allowed to go only through them (there is no opening on the top). Compare that to the v5.0 heatsink, which uses a regular style fan and the fins are placed like rays.

The thickness of the heatsinks is also different.
http://www.badcaps.net/forum/attachm...1&d=1499545505
On the left side of the above picture is the v5.0 heatsink and on the right is v6.5. Overall v6.5 has much thicker base, which is better, because it allows for a better heat flow from the GPU core to the fins.

But there is a twist. Look at the bottom of these:
http://www.badcaps.net/forum/attachm...1&d=1499545505
On the left again is v5.0 and v6.5 on the right. Version 5.0 has a thin copper heat spreader, whereas v6.5 does not. Makes one wonder which is better: thinner heatsink with a thin copper heat spreader, or an overall thicker heatsink without the copper heat spreader. Unfortunately, both of these heatsinks are too small for the TDP of the 8600 GT, so it is not possible to determine that with this GPU. Perhaps with a lower TDP GPU, it may be possible.

Finally, here is a shot of the squirrel cage fan, a Protechnic Magic MGA5012XR-O10, rated for 0.19 Amps @ 12V:
http://www.badcaps.net/forum/attachm...1&d=1499545505

And just for fun, the GPU core:
http://www.badcaps.net/forum/attachm...1&d=1499545505

Now here is something interesting: nVidia lists the 8600 GT as being 43 Watts TDP on paper. Meanwhile, they list the 9400 GT (a shrunk-down 8500 GT core) as being a 50 W TDP GPU. But something doesn’t quite add up, because I have an XFX GeForce 9400 GT with a heatsink somewhat similar in size to the heatsinks shown above. It also uses a regular 50 mm fan going at full blast on 12V. Yet, no matter what load I put on that 9400 GT, it won’t go over 52C with its stock heatsink. So I think nVidia really underestimated the TDP of the 8600 GT – either that, or they just didn’t care to put a proper heatsinks on it.

Last edited by momaka; 07-08-2017 at 02:30 PM..
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Old 07-12-2017, 06:02 PM   #4
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Default Re: XFX GeForce 8600 GT [PV-T84J-UDD3 V6.5] GPU recap

Quote:
Originally Posted by momaka
1Lol, look at these c[r]aps! They are a hair away from open-circuit. . Not even two (2) nanoFarads of capacitance in any of them! I think it is an absolute miracle this video card worked at all!
Didn't you find 3300F 6.3V KZG which failed even more epically, IE they were completely open-circuit? Who woulda thought that KZG had it in them to actually drift more out-of-spec than Sacon FZ?

That said, those PSA polymers would look much better in place of the "blue" FZ. It probably wouldn't hurt to fill those empty SMD cap pads with replacements. Probably not worth it on an 8600 GT, though.

Last edited by Wester547; 07-12-2017 at 07:01 PM..
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Old 07-15-2017, 02:42 PM   #5
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Default Re: XFX GeForce 8600 GT [PV-T84J-UDD3 V6.5] GPU recap

Quote:
Originally Posted by Wester547 View Post
Didn't you find 3300F 6.3V KZG which failed even more epically, IE they were completely open-circuit? Who woulda thought that KZG had it in them to actually drift more out-of-spec than Sacon FZ?
I've found plenty of caps fail open-circuit. So yes, Sacon FZ is not the worst in that regard.

But what I find amazing here is how the video card continued to function (or the GPU and RAM VRMs didn't die, at least) with almost no capacitance left - that's a pretty robust VRM design, IMO. Though, perhaps it is also worth noting here that both the GPU and RAM VRMs employ very low inductance inductors. This means the VRMs run at a very high frequency - high enough where ultra-low ESR probably matters even more than the capacitance. With that said, I probably can remove all of the electrolytic capacitors and go 100% ceramic caps. But I don't feel that bored... yet.

Also worth noting is that the PCB near the VRM coils runs very hot on this card (at least with a high ambient temperature of 30C/86F). I would guess that's just another factor that helped the Sacon FZ caps go bad quicker.

Quote:
Originally Posted by Wester547 View Post
That said, those PSA polymers would look much better in place of the "blue" FZ. It probably wouldn't hurt to fill those empty SMD cap pads with replacements. Probably not worth it on an 8600 GT, though.
I will fill them, eventually.

The 8600 GT runs Valve's Source Engine pretty well. Thus, for an older card to play TF2, Gmod, Portal 2, or similar... it is more than enough.

So I think it is worth it overall.

Last edited by momaka; 07-15-2017 at 02:44 PM..
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Old 07-15-2017, 04:24 PM   #6
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Default Re: XFX GeForce 8600 GT [PV-T84J-UDD3 V6.5] GPU recap

Quote:
Originally Posted by momaka
I will fill them, eventually.

The 8600 GT runs Valve's Source Engine pretty well. Thus, for an older card to play TF2, Gmod, Portal 2, or similar... it is more than enough.

So I think it is worth it overall.
The Source Engine is pretty "dated" at this point... at least that's what modern "tech" people would say. That anything made within the last five years or older is automatically obsoleted.

That said, the 8600 GT was an underwhelming card even when it was first released, over a decade ago.
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Old 08-10-2017, 01:16 AM   #7
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Default Re: XFX GeForce 8600 GT [PV-T84J-UDD3 V6.5] GPU recap

cool. i had a not bootable gtx 560, then it when missing.
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